schema/types: remove unused error type
schema/types: remove unused error type

iaguis/appc-spec,alban/appc-spec,krnowak/appc-spec,squeed/spec,zenlinTechnofreak/spec,craimbert/spec,jonboulle/spec,tklauser/spec,alban/appc-spec,stufflebear/spec,squeed/spec,apcera/appc-spec,dustymabe/spec,marineam/spec,apcera/appc-spec,zenlinTechnofreak/spec,dgonyeo/spec,squeed/spec,ChengTiesheng/spec,appc/spec,jonboulle/spec,krnowak/appc-spec,3ofcoins/appc-spec,craimbert/spec,3ofcoins/appc-spec,dgonyeo/spec,yifan-gu/spec,dustymabe/spec,stufflebear/spec,krnowak/appc-spec,appc/spec,iaguis/appc-spec,iaguis/appc-spec,dustymabe/spec,ChengTiesheng/spec,tklauser/spec,stufflebear/spec,endocode/appc-spec,dgonyeo/spec,marineam/spec,3ofcoins/appc-spec,yifan-gu/spec,apcera/appc-spec,zenlinTechnofreak/spec,appc/spec,craimbert/spec,endocode/appc-spec,tklauser/spec,jonboulle/spec,marineam/spec,ChengTiesheng/spec,alban/appc-spec,yifan-gu/spec,endocode/appc-spec